Android Wi-Fi源码分析之WifiService操作Wi-Fi(一):分析Wifi.c中的wifi_load_driver()函数

Wi-Fi源码分析之WifiService操作Wi-Fi(一)

分析Wifi.c中的wifi_load_driver()函数

int wifi_load_driver(){    ALOGD("============wifi_load_driver================");    /* WIFI_DRIVER_MODULE_PATH定义wlan driver的文件路径名. 我这里并没有定义 */#ifdef WIFI_DRIVER_MODULE_PATH     ALOGD("============wifi_load_driver:WIFI_DRIVER_MODULE_PATH================");    char driver_status[PROPERTY_VALUE_MAX];    int count = 100; /* wait at most 20 seconds for completion */    if (is_wifi_driver_loaded()) {        return 0;    }    /* DRIVER_MODULE_PATH里保存WIFI_DRIVER_MODULE_PATH宏定义的文件路径名;     * 如果WIFI_DRIVER_MODULE_PATH定义了就在此处通过       insmod向内核添加wlan driver*/    if (insmod(DRIVER_MODULE_PATH, DRIVER_MODULE_ARG) < 0)        return -1;    /* FIRMWARE_LOADER 变量指向 WIFI_FIRMWARE_LOADER宏定义的 wlan 固件加载程序文件路径名     * DRIVER_PROP_NAME 的值为"wlan.driver.status";     * 如果没有指定 wlan 固件加载程序,则直接设置"wlan.driver.status"的属性为"ok"     * 否则                                   通过"ctl.start"方式来启动 wlan 固件加载程序     * */    if (strcmp(FIRMWARE_LOADER,"") == 0) {        /* usleep(WIFI_DRIVER_LOADER_DELAY); */        property_set(DRIVER_PROP_NAME, "ok");    }    else {        property_set("ctl.start", FIRMWARE_LOADER);    }    sched_yield();    while (count-- > 0) {        if (property_get(DRIVER_PROP_NAME, driver_status, NULL)) {            if (strcmp(driver_status, "ok") == 0)                return 0;            else if (strcmp(DRIVER_PROP_NAME, "failed") == 0) {                wifi_unload_driver();                return -1;            }        }        usleep(200000);    }    property_set(DRIVER_PROP_NAME, "timeout");    wifi_unload_driver();    return -1;#else    /*如果没有定义宏WIFI_DRIVER_MODULE_PATH,则直接设置"wlan.driver.status"的属性为"ok"*/    property_set(DRIVER_PROP_NAME, "ok");    return 0;#endif}